In the contact spring arrangement disclosed in German patent specification No. 1,213,917, a substantial portion of the force exerted on the armature by a permanent magnet is stored in a double contact spring. Accordingly, practically no excitation energy is required to provide the contact force. In the known arrangement, an actuating nipple is disposed between the free ends of a bifurcated spring which has the same flexibility in both directions of its actuation. It is necessary that the path of travel of the armature is greater than the contact clearance by the travelling distance required by the spring in either direction of actuation. Furthermore, since the bifurcated spring ends exhibit the same flexibility at the opening as at the closing of the contact couple, there is a danger that a contact couple of the relay is closed while another contact couple has become stuck or welded together.
In view of this problem, German Auslegeschrift No. 2,454,967 suggests an arrangement in which the contact couple is positively and forcibly opened, whereas the closing of the contact couple is done solely by tensioning the contact spring. However, this arrangement allows only a small proportion of the pull provided by the armature to be stored in the contact spring.
It is an object of the present invention to provide a contact spring arrangement in which, in case of a sticking of the contact couple, the contact spring will not substantially be bent by the actuation of the armature to open the contact, while a bending of the contact spring is ensured in the closed condition of the contact couple.
It is a further object of the present invention to provide an arrangement as set forth above, which is easy to manufacture and assemble with a minimum of structural components.